Expansion joint for concrete roadways



Oct. 29, 1946. R. c. OLMSTED ETAL I 2,410,099

I EXPANSION JOINT FOR CONCRETE ROADWAYS Filed Dec. 18, 1943 s'Sheets-Sheet 1 FIG..1.

INVNTORS RUSSELL c OLMSTEO ART/1 H. HARRIS.

ATTORNEY vGet. 29, 1946. R. c. OLMSTED ET AL' E XP A NSION JOINT FORCONCRETE ROADWAYS Filed Dec. 18,-.1943 3 Sheets-Sheet 2 Q INVENTORSRUSSELL C. 04/145750 ART/ 1? H. /-/AR/?/$ ATTORNEYS Oct. 29, 1946. I R.c. OLMST-ED ET'AL 2,410,099

EXPANSION JOINT FOR CONCRETE ROADWAYS Filed Dec. 18, 1943 5 Sheets-Sheet3 '9 fi'o I I l l J i I N i 1::-

I I i I INVENTORS k RUSSELL C OLMSTED I ARTHUR H HARP/5 ATTORNEYSPatented Oct. 29, 1946 ROADW AYS Russell 0. Olmsted, Harrington Park, N.J., and 1 Arthur H. Harris, New Britain, Conn.; Hazel B. Olmsted,administrat-rix of said Russell 0. Olmsted, deceased, assignor tosaidHarris Application December 18, 1943, Serial No. 514,754

3 Claims. (Cl. S ip--18 This invention relates to expansion joints forconcrete roadways, and other like concrete construction wherein theadjacent ends of two concrete slabs are to be joined together.

In the building of concrete roads, it is the practice to lay the same inslabs with a compressible filler strip interposed between the adjacentedges of'the slabs to accommodate expansion of the slabs. Also, it isthe practice to connect adjacent slabs by dowels which bridge the jointstherebetween to prevent rising movement of the adjacent slabs relativeto each other. Therefore, the main feature of this invention is toprovide an expansion joint which permits the slabs to expand andcontract while securely bonding, the same together to prevent verticalmovement of adjacent slabsrelative to each other.

, Another feature of the invention resides in a metal dowel structurewhich is manually fabricated in a manner to avoid the necessity ofwelding which is costly and laborious.

- Another feature of they invention resides in a dowel constructionwhich is normally rigid when placed in position'upon a sub-gradepreparatory to the pouring of the concrete slabs, and which embodiesrupturable means which functions when the concrete becomes set due tonormal contraction of the slabs, the dowel when said means is rupturedbeing of such strength as to arrest any tendency of the slabs to riserelative to each other.

e A further feature of the invention is the provision of a dowel typeexpansion joint which is simple and inexpensive of construction, easy toassemble on a job, and strong and durable for the purposes intended.

Other novel features of the invention will become apparent as thefollowing specification is read in conjunction with the accompanyingdrawings, in which,

. Figure 1 is a top plan view of an expansion dowel joint constructed inaccordance with our invention.

Figure 2 is an end elevational view of the dowel joint embedded inadjacent concrete slabs, the latter being shown in section.

I Figure 3 is an enlarged fragmentary vertical transverse sectional viewon the line 3-' 3 of Figure 1.

Figure 4 is a vertical transverse sectional view on the line 44 ofFigure v3.

Figure 5 is a fragmentaryvertical sectional view illustrating a modifiedform of expansion dowel joint constructed in accordance with ourinvention. 1

2 Figure 6 is a vertical transverse sectional view on the line 6-6 ofFigure 5.

Figure 7 is a perspective view of one of the coupling plates. Referringto the drawings by reference'characters, the numeral I designates afiller strip of any conventional resilient composition material which isdisposed on edge and of a height approximating the thickness of theconcrete slabs A-A to be joined and between which it is interposed. Thelength of the filler strip l0 depends upon the length of the fabricatedstructure which is composed of a plurality of suitably spacedtransversely disposed expansion dowel units ll. Eachexpansion dowel unitll includes a pair of metal plates l2-l2 of rectangular shape hav-' ingtheir four corners bent rearwardly to provide pointed prongs P. Theplate I2 has a centrally located rectangular opening l3, upper and lowerbolt'o'penings l4 l4, and horizontal upper and lower slots and 16respectively, said slots being disposed adjacent-the respective top andbottom edges of the central slot 13. The metal material between theslots l5 and I6 and the adjacent ends of the slot l 3 is outwardlyoffset for reasons hereinafter explained. The plates l2-I2 at the topand bottom ends of the slot [3 are provided with horizontal outwardlyextending flanges l1 and I8 respectively. The plates l2--!2' arerespectively applied againsto-pposite sides of the strip I0 with theopenings l4 therein'in registration with a similar sizepassage [9-provided in the strip 10'. The plates 12 'are applied with the prongs Pfacin the strip and which embed themselves therein. However, before theplates l2 are applied in position, each plate is connected to a framestructure F, so that a frame structure extends from each side of thestrip l0.

Each frame structure F includes a supporting member formed of a lengthof metal channel stock, preferably strip steel, which is bent at 2| toform a'horizontal channel track 22 and a vertical leg 23. The sideflanges 24-24 of the track 22 at the inner endsthereof terminate shortof the web 25 thereof to provide a tongue extension 26 which is bentdownwardly at right angle and which lies behind the off t portinn of t ete l2 adjacent the slot Hi. The terminal end of the tongue extensionpasses forwardly through the slot is and terminates in an upturned hookportion 21. It Will therefore be seen that the inner end of thesupporting member 2a is fixedly secured to the plate 12 and its weightrests upon thefiange l8. The leg 23 extends vertically and has itslower, end connected to a base member 28.

The base member 28 is of metal channel stock and is placed upon thesub-grade C of a roadway with its open side up for a reason to behereafter explained. The leg 23 may be connected to the base member invarious ways but we have shown the web portion of the leg as havingportions 29 extending through openings in the base member, whichportions are upset or headed as best illustrated in Figure 3. The basemembers 28 extend parallel to the strip H] at respective sides thereofand are of a length substantially equal to the length thereof. The webportions of the base members 28 are provided with suitably spacedapertures 3|] through which nails or spikes 3| may pass and be driveninto the sub-grade C for rigidly holding the multiple dowel jointstructure in a set position.

Each frame structure F also includes a guide member 32 which isconstructed of a length of metal channel stock, preferably strip steel,which is bent inwardly as at 33 to provide a horizontal guide portion 34and a downwardly extending end wall portion 35. The guide member 32comprises side flanges 36-36 and a connecting web 31. The guide member32 is complementary to the horizontal track 22 and is disposed with itsopen side facing inwardly. The side flanges 3 6--36 of the end wallportion are cut short of the web 31 to rest on the flanges 24 adjacentthe leg 23, while the extending portion 38 of the web 31 extends througha slot in the web 22 and has its end upset or headed.

The inner end of each guide member 32 has a tongue extension 39 formedon the web 31, which tongue extension is bent upwardly at right angleand lies between the plate l2 and the strip I0, the terminal end of thetongue extension being formed with a down-turned hook 40 which passesoutwardly through the slot |5 and hookingly engages the adjacent offsetportion of the plate I2.

The inner end of the web 31 is disposed beneath and is braced by theflange Before positioning the frame structure F--F at opposite sides ofthe strip In, a dowel beam 4| is inserted through th passage la in thestrip so as to extend a substantially equal distance be yond oppositesides of the strip. After the dowel beam 4| has been thus positioned,the open ends of the frame structures F-F are inserted onto the ends ofthe beam, said open ends carrying the plates |2-|2. The frame structuresare slid inwardly over the ends of the beam until the plates |2-|2flatly engage opposite sides of the strip w where the plates are pressedinwardly to cause the prongs P to become embedded in the strip H). Theplates l2 are now in a position to be connected to the strip ID by arupturable fastening means now to be described.

The rupturable fastening means comprises headed bolts 42 which passthrough the alined holes I4 in the plates |2--|2 and through alinedholes 43 in the strip NJ. The headed ends of th bolts 42 engage one ofthe plates l2 while the threaded ends of the bolts extend beyond theother plate l2 and receive fiat resilient clamping plates; Each clampingplate. 44. includes a pair of spaced opposed spring tongues 45-45 whichreleasably interlock with the threads of the bolt. The clamping plates44 are pushed onto the threaded end of the bolts and flatly engage theadjacent plate I2. Thus the frame structures F--F are connected toopposite sides of the strip in such manner that any expansion movementof. the slabs A-A will cause the bolt connections to break due to thefact that the resilient clamping plates 44 will be pulled from thethreaded ends of the bolts 42. The dowel beam 4| bridges the jointbetween adjacent slabs and prevents upward movement of one slab relativeto the other.

Whereas the dowel beam 4| may be of a length substantially equal to thecombined lengths of the frame structures FF and thickness of the stripID, We prefer to make the same shorter, and to compensate for thisdifference in length, resilient filler blocks 46-46 are placed in theframe members between the ends of the dowel bar 4| and the end wallportions 35 as best seen in Figure 2. The resilient filler blocks 46 maybe made of cork, rubber, or the like, and when compressed, they place aslight initial tension upon the rupturable fastening means.

By reason of the channel fram structures F-F,

the same will freely slide relative to the dowel beam 4| when the slabsA-A expand and the rupturable fastening means has released the framestructures from. their original connections with the strip l0.

, The channel base members 28 have their open sides face up to receivethe concrete fill and prevent the formation of voids in the slabs A-Awhen set.

In Figures 5 to 7 inclusive we have illustrated a modified form of ourinvention and like parts heretofore described are designated bycorresponding reference characters. In this form of the invention theends of the dowel beam 4| slidably extend into frame structures F'--F',respectively disposed at opposite sides of the strip ill. Each framestructure F includes a straight horizontal track 22" of metal channelstock, the outer end of which is formed with a web tongue extension 38which extends through a slot in the. web 31 of a vertical supporting leg23' and which has. its end headed or upset. The leg 23 is formedintegral with the horizontal guide member 34' which is disposed parallelto and in spaced superposed relation to the track 22. The lower end ofthe leg 23' is fixedly secured. to the U-shaped base member 28.

The inner ends of the track 22 and guide member 34' terminate invertical alinement. and the webs thereof adjacent said ends are providedwith vertically alined slots l5. The inner ends of the track and guidemember are fixedly connected to a metal plate l2", which plate has acentral rectangular shaped opening l3 which registers with the openingl9 in the strip l0. Flanges extend outwardly from the top and bottomends of the slot I3" and have inwardly extending tongues 39 which enterthe respective slots l5. The plates l2 are secured to opposite sides ofthe strip ID in the same manner as before described, namely by bolts 42passing through alined openings l4 in the plates and. openings 43 in thestrip Ill. Releasable resilient clamping plates 44 are applied to thethreaded ends of the bolts to form the rupturable connection between thedowel frame structures F--F" and the strip Hi. The modified constructionof expansion dowel joint functions in the same manner as that shown inFigures 1 to 4 inclusive, therefore a further description is notbelieved necessary.

While we have shown and described what we consider to be the mostpractical embodiments of our invention, we wish it to be understood thatsuch changes in design and materials as come within the scope of theappended claims may be resorted to without departing from the spirit ofthe invention.

Having thus described the invention, what we claim as new is:

1. An expansion joint structure comprising in combination, afiller stripadapted to close the joint between adjacent ends of a pair of concreteslabs, said filler strip having a transverse passage therein, a dowelbeam freely passing through said passage and having its ends disposedbeyond opposite sides of said filler strip ,'a pair of metal framestructures having their respective inner ends fitting against oppositesides of the filler strip and slidably receiving the respective ends ofthe dowel beam, each of said frame structures including parallel top andbottom frame members of channel shape in cross section with the opensides thereof in confronting relation, legs carried by the outer ends ofthe frame structures for supporting the same in an elevated positionabove the subgrade of" a roadway, and rupturable fastening means forsecuring the inner ends of the frame structures to opposite sides of thefiller strip, said rupturable fastening means being adapted to breakunder expansion stresses of the connected slabs.

2. An expansion joint structure as set forth in claim 1 in which therupturable fastening means to the inner ends respectively of the framestructures, said plates having openings therein conforming in shape andsize to that of said passage, said plates being respectively disposedagainst opposite sides of said filler strip with the openings therein inregister with the passage, rupturable fastening means securing saidplates to said filler strip, a dowel beam freely passing through thepassage with its ends respectively extending into the frame structuresand snugly disposed therein, and each attaching plate being secured tothe respectiveframe structure by an offset portion on the plate and ahook on the frame structure engaged with said offset portion.

RUSSELL C. OLMSTED. ARTHUR H. HARRIS.

Certificate of Correction Patent No. 2,410,099. v October 29, 1946.RUSSELL C. OLMSTED ET AL.

It is hereby certified that error appears in the above numbered patentrequiring correction as follows: In the grant, lines 14 and 15, afterthe Word heirs strike out or assigns, and Hazel B. Olmsted, asAdministratrix, her successors; and that the said Letters Patent shouldbe read with this correction therein that the same may conform to therecord of the case in the Patent Ofiice.

Signed and sealed this 24th day of December, A. D. 1946.

LESLIE FRAZER,

First Assistant Oommz'ssioncr of Patents.

